Study Set Content:
layer of thick-walled cells
Hypodermis
Leaves of Aquatic Areas characteristics
less xylem than phloem, mesophyll not differentiated into palisade and spongy layers, has large air spaces
Submerged leaves of plants that grow in water usually have considerably less xylem than phloem, and the mesophyll, not differentiated into palisade and spongy layers, has large air spaces
Leaves of Aquatic Areas
Help the plant in climbing or in supporting weak stems when curled tightly around more rigid objects
Tendrils
sudden, rapid growth cells on the opposite side and start curling in the direction of contact within a minute or two when you lightly stroke it
Healthy Tendrils
If contact is very brief tendril tends to
reverses movement and straightens out again
If tendril encounters a suitable solid support stimulation is?
continuous
tendril coils tightly around
the support as it grows
as tendrils develop
they become coiled like a spring
Members of the Pumpkin family(Cucurbitacaea) produce tendrils
up to 3 decimeters(1 foot) long
Direction of coil reverses; schlerenchyma and collenchyma cells
develop in the vicinity of contact
provide rigid support
Sclerenchyma cells
Makes very strong but flexible attachment that protects the plant from damage during high winds
Collenchyma cells
impart flexibility
Collenchyma cells
Tendrils of sweet pea are modified leaves that aid
in climbing
sweet pea
(Lathyrus odoratus)
Reduces water loss
Spines, Thorns, and Prickles
Protect the plant from browsing animals
Spines, Thorns, and Prickles
Leaves of many cacti and another desert plants-spines
Spines, Thorns, and Prickles
Photosynthesis occurs in green stems
Spines, Thorns, and Prickles
